12 Jan. New alloy blends optics and electronics
Scientists at Forschungszentrum Jülich and the Leibniz Institute for Innovative Microelectronics (IHP) have developed a new compound that is compatible with the chip industry’s standard CMOS process.
The alloy consists of four elements: carbon, silicon, germanium, and tin, abbreviated as CSiGeSn. All four elements belong to the same main group elements. Dr. Dan Buca from Forschungszentrum Jülich says, “We have achieved an ambitious goal: the ultimate semiconductor based on the fourth main group.” For a long time, the production of the new compound was considered virtually impossible. According to the researchers, it was only through precise adjustment of the manufacturing processes that they succeeded in combining these opposites – using an industrial CVD system from Aixtron. No special equipment was required, the same device that is also used in chip production.
Scientists Dr. Dan Buca (left) and Andreas Tiedemann are at the CVD system from Aixtron, which coats wafers with the new alloy. Image: Forschungszentrum Jülich / Jenö Gellinek
New approaches in silicon photonics
The researchers explain that the new alloy will allow properties to be fine-tuned to such an extent that components can be created that would not be possible with pure silicon. These could be used in optical components or quantum circuits, for example. The structures can be created directly on the chip during manufacture. The researchers had already succeeded in combining the three elements silicon, germanium, and tin to develop transistors, photodetectors, lasers, and LEDs – as well as thermoelectric materials.
Schematic 3D image of the CGeSn/GeSn MQW heterostructure. Image: Advanced Materials, Volume: 37, Issue: 37, DOI: (10.1002/adma.202506919).
The addition of carbon now allows for more specific adjustment of the band gap. This is crucial for electronic and photonic behavior. “Many optical applications from the silicon group are still in their infancy,” explains Buca. “There are also new opportunities for the development of suitable thermoelectrics to convert heat into electrical energy in wearables and computer chips.”
The material was also used to create the first LED based on so-called quantum well structures made of the four elements – a significant step toward new optoelectronic components.
Original publication
[Omar Concepción et al.: Adaptive Epitaxy of C-Si-Ge-Sn: Customizable
Bulk and Quantum Structures; Advanced Materials, Volume: 37, Issue: 37, 2025, DOI 10.1002/adma.202506919]
Source: www.fz-juelich.de
Imag: Forschungszentrum Jülich / Jenö Gellinek